Upper Little D has a couple of rather fat, brave, even militant squirrels in the trees/brush there too. Leave the lid off your ammo can and they will rifle (ha, ha) through it and see what is in there to get to.
My son learned this the hard way and ended up with a bunch of work. He brought a bag of sunflower seeds on one of our trips and had them in the ammo can. I warned him about seeds, if the shells get on the ground, he gets to pick them up. He left the ammo can open for not even 5 minutes unattended and the squirrel had the bag out, chewed open and about 1/2 of the seeds shelled and spread all over. Took my son 30 minutes to clean it all up...
Only consolation is that we figured the squirrel would be looking for a some cool water, the seeds were the hot and spicey ones.